Seal for centrifugal separators



Patented July 20, 1937 I UNITED STATES PATENT OFFICE 2,087,726 I SEAL FOR. CENTRIFUGAL SEPARATORS Wilmer H. Bath, Conshohocken, Pa., assignor to The Sharples Specialty Company, Philadelphia, Pa., a corporation of Delaware Application May 6, 1933, Serial No. 669,701

2 Claims. (01. 286-5) The present invention relates to the art of centrifugal separator of the Sharples type, illuscentrifugal separators and it was conceived as trating the application of the invention thereto. an improvement with respect to the type of cen- Referring to the drawing by reference charactrifugal separator described and claimed in the ters, the numeral Ill indicates a support adapted 5 patent to Leo D. Jones and Arthur U. Ayres, No. to be secured in gas-tight relationship with re- 1,634,246, patented June 28, 1927. In that patent spect to a gas-tight casing in surrounding a a number of features are disclosed relating to the centrifugal rotor, the general arrangement of centrifugal treatment and discharge of liquids casing and rotor being preferably similar to that within a conditioned atmosphere. Among the illustrated in the joint patent to Jones and Ayres features described in that patent, an important referred to above. The support is provided with modification relates to the subjection of liquids an annular projection ll adapted to be received discharged from a centrifugal rotor in a finely within the casing and is recessed at l2 to aflord dispersed form to the conditioning effect of a provision for t e d ve Spindle 0f the machine, rarefied atmosphere which is maintained in the the spindle being provided with a. suit-able coucasing surrounding the rotor. pling nut M at its lower end in order that it Serious difiiculties are encountered in attempts may be detachably secured to the centrifugal to maintain seals which are both effective and rotor. durable between relatively rotatable surfaces of A sleeve 15, which is designed to receive the the type involved in the bearing and driving ardrive spindle and support the bearing assembly a ements in this type of machine. Seals of the and drive pulley, is secured at its lower end to ordinary packing type are unsatisfactory for such the support ID. This sleeve is provided with a use because of their rapid destruction under the shoulder l6 adapt o pp a bearing s high heat generated by the rotation of the bowl b y n by which a drive pulley is mounted for ofahighspeedcentrifug-al separator under ahigh rotation wi h r p t h pp r v friction load and by the vibration encountered the pulley being Connected With t dri in such a separator. Liquid seals are subject to Sp n by a ach e Couplin C ect on in the objection that they are complicated and cated generally at difficult to maintain. They are also subject to C nt u a s pa t having t at s d the objection that the heat generated in th scribed above are unsuited to the maintenance of tation of the body of the sealing liquid t d a controlled atmosphere, and particularly of a to volatilize the liquid and thus contaminate the uu Within the casing which surrounds t conditioned atmosphere, thereby sometimes tend- 1'01101, because of leakage of air between t e S 1 ing to defeat the very object for which t are portingsleeve l5 and the pulley l8 through the designed. This last-named obje tion presents bearing assembly I! and thence through the space unusual difiiculties in cases where it is desired. surrounding the spindle l nw d y to t to maintain a vacuum within the frame of t main casing of the machine. In order to obviate machine and requires u us al care i operation. such leakage, in the practice of the present in- It has been a primary bj t of t present vention an annular flange 2!! of substantial radial vention to provide a l whichris of a Simple extent is formed upon the sleeve I5 and the 4 and inexpensive nature and is peculiarly applicapulley provided complemental Surface ble to the problem f maintaining a Vacuum With 2| spaced in closely contiguous relationship with in the frame and rotor of a centrifugal separator. respect to the upper face of the flange An important feature of the arrangement by The arrange11ent9f these two Surf acesm close f which these objects have been attained consists g mg: :3:gi ggg g figg gfigggg g gfi 2 1 2: g gif gfi f f f i g; ig the portion of the bearing assembly communifngress g sg i g gg g i e cating with the interior of the main frame of the Further objects and advantages of the invenmachme' when power 15 applied to the pulley l8 to rotate the spindle l3 andthe rotor of the tlon and the manner 111 Whlch they have been machine, the rapid rotation of the surface 2| attained Wi l be O o from a reading of the causes rotation of the air column between the following detailed description in the light 0f the flange 20 and surface 2| and causes an outward attached drawing, in which, radial pressure within this column by reason of The Si e figure is a central vertical section the centrifugal force exerted upon the column through the bearing and drive connections of a in this manner.

While a seal having the features described above is of great assistance in maintaining a vacuum, turbulence within the column of air between the flange 20 and surface 2| sometimes 5 seriously impairs the maintenance of such a vacuum. An important feature of the invention, therefore, consists in the provision of an arrangement whereby turbulence can be avoided and partially isolated zones of differential pressure set up between the surfaces 20 and 2|. To this end, a nested projection and groove arrangement is provided between these surfaces. In the embodiment illustrated, an annular projection 22 interrupts the inner surface of the flange 20 and the surface 2| of the pulley is interrupted by an annular groove 23 adapted to receive this projection in nested relationship. In the operation of the machine, the column of air lying radially within the projection 22 is subjected to a centrifugal force which is considerably less than that generated upon the column of air lying radially without this projection. Zones of high and low pressure are thus obtained which are substantially physically isolated from each other, thus 25 affording a pressure seal to prevent ingress of air to the interior of the frame.

While the features of the invention have been described in detailfit will be obvious that they are susceptible of considerable modification.

Thus, while a substantially radial flange has been indicated at 20, it will be obvious that a-flange extending in another direction might be substituted so long as it affords a surface which is of substantial extent in its radial projection.

While the features of the invention were especially conceived with reference to a centrifugal separator, they are doubtless: capable of other applications. In view of these facts, I do not wish to limit myself except by the scope of the subjoined claims.

What I claim is:

1. In a machine having a rapidly rotating rotor and a surrounding housing adapted to have a subatmospheric pressure maintained therein, centrifugal seal means for sealing between said housing and said rotor comprising surfaces of substantial radial extent between said rotor and said housing, said surfaces being so related'as to maintain at all times a thin column of air therebetween in which, upon rotation of the rotor, centrifugal force acting thereon builds up a pressure sufficient to prevent the ingress of air between said members.

2. In a machine having a rotor and a surrounding housing adapted to have a sub-atmospheric pressure maintained therein, a rotatable drive spindle secured to the rotor and extending through said housing, centrifugal seal means for sealing between said housing and said rotor comprising a member having a surface of substantial radial extent carried by said spindle and a stationary member having a surface of substantial radial extent contiguous and parallel to said first named surface fixed with respect to the housing, an annular projection upon one of said surfaces and an annular depression in the other of said surfaces adapted to receive said annular projection in nested relationship, the contiguous and parallel relation of said surfaces being such as to maintain at all times a thin column of air therebetween in which, upon rotation of the spindle, centrifugal force acting thereon builds up a pressure sufflcient to prevent the ingress of air between said members.

WILMER H. BATH. 

